BMI Calculator

The BMI is an indirect measure of body composition, based on your height and weight. However, the BMI is not for everyone. If you are muscular you will appear to have a very high BMI, as muscle weighs up to two and a half times as much as fat. Use the calculator to determine your BMI.

Height (cm)
Body Weight (kg)

 BMI Chart

< 18.5 Underweight
18.5–24.9 Healthy weight range
25.0–29.9 Overweight
30.0–34.9 Obesity I
35.0–39.9 Obesity II
≥ 40.0 Obesity III


Generally, the higher your BMI, the higher your health is at risk.

BMI Information

BMI is less accurate for assessing healthy weight in some groups of people, as it does not distinguish between the proportion of weight due to fat or muscle. BMI is therefore less accurate in certain groups, including:

  • certain ethnic groups such as Pacific Islander populations (including Torres Strait Islander peoples and Maori), Aboriginal peoples, South Asian,
  • Chinese and Japanese population groups
  • body builders or weight lifters
  • some high performance athletes
  • pregnant women
  • the elderly
  • people with a physical disability
  • people with eating disorders
  • people under 18 years
  • and those with extreme obesity.


Now measure your waist size.

Why measure waist circumference?

Carrying excess body fat around your middle is more of a health risk than if weight is on your hips and thighs. Waist circumference is a better estimate of visceral fat, the dangerous internal fat which coats the organs. It is therefore a more accurate predictor of cardiovascular risk,  type 2 diabetes  in women and  metabolic syndrome.

How do I measure my waist circumference?

To find out your level of risk, it is important to measure your waist circumference accurately.

  • Place the tape measure directly on your skin, or over no more than one layer of light clothing.
  • The correct place to measure your waist is halfway between your lowest rib and the top of your hipbone. This is roughly in line with your belly button.
  • Breathe out normally and measure.
  • Make sure the tape is snug, without squeezing the skin.

Waist circumference and disease risk

Waist circumference thresholds which indicate increased risk of disease are below:

For women:

  • risk is increased at more than or equal to 80 cm
  • risk is high at more than or equal to 88 cm

For men:

  • risk is increased at more than or equal to 94 cm
  • risk is high at more than or equal to 102 cm for men


Limitations of waist circumference

Waist circumference is less accurate in some situations, including pregnancy, medical conditions where there is distension of the abdomen, for certain ethnic groups and for children and young people.